The present invention relates to an air cleaner casing that has a looped application surface to which an adhesive for securing a filter element is applied. The present invention also relates to an air cleaner that includes the casing and to a method for manufacturing the air cleaner casing.
Such an air cleaner has been disclosed in, for example, Japanese Laid-Open Patent Publication No. 58-155215. The air cleaner disclosed in the above publication includes a cylindrical filter element located in a cylindrical casing. The filter element includes a cylindrical filter and a disk-like support frame located at an end of the filter. The outer peripheral edge of the support frame is secured to a looped step portion formed on the inner surface of the casing with an adhesive. The opening at an end of the casing is covered with a cover. The cover is secured to the end of the casing with an adhesive or by ultrasonic welding.
Like the air cleaner of Japanese Laid-Open Patent Publication No. 58-155215, air cleaners that have a looped application surface such as a step portion for applying an adhesive to the casing may possibly have the following problem. That is, since the adhesive has flowability, the adhesive applied to the application surface may flow out to the inner side. Thus, the adhesive does not stay on the application surface, and it is difficult to secure the filter element in a stable manner. However, in order to keep the adhesive on the application surface, the amount of adhesive used is increased.